Swasdipan S, Bielefeldt-Ohmann H, Phillips N, Kirkland P D, McGowan M R
School of Veterinary Science, University of Queensland, Brisbane, Australia.
Vet Pathol. 2001 May;38(3):275-80. doi: 10.1354/vp.38-3-275.
Despite the importance of congenital viral infections in both veterinary and human medicine, only limited experimental work has been carried out to elucidate the mechanisms involved in transplacental virus infections. To further an understanding of fetal infection with pestiviruses, the distribution of bovine pestivirus in the uterine and fetal tissues of ewes in early pregnancy, following a natural route of infection, was investigated. On the 18th day of pregnancy, nine ewes were inoculated by the intranasal route with 1 x 10(5) 50% tissue culture infective doses of an Australian isolate of noncytopathic bovine pestivirus (bovine viral diarrhea virus genotype 1). All ewes were ovariohysterectomized at approximately 100 hours postinfection. Samples from the reproductive tract and conceptus were examined histologically and tested for bovine pestivirus by nested reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry and for interferon-tau mRNA expression by nonnested RT-PCR. Although no histopathologic changes were observed in the maternal or fetal tissues, virus was detected in the reproductive tract of all nine ewes and in all of the conceptuses examined. At the time of surgery, only two of the nine ewes were demonstrably viremic. This study demonstrates that bovine pestivirus can spread from a natural site of infection to the ovine fetus within 4 days in the absence of maternal immunity and despite the presence of interferon expression in the reproductive tract.
尽管先天性病毒感染在兽医和人类医学中都很重要，但为阐明经胎盘病毒感染所涉及机制而开展的实验工作却很有限。为了进一步了解瘟病毒对胎儿的感染情况，我们对自然感染途径下怀孕早期母羊子宫和胎儿组织中牛瘟病毒的分布进行了研究。在怀孕第18天，通过鼻内途径给9只母羊接种了1×10(5) 50%组织培养感染剂量的一株澳大利亚非细胞病变性牛瘟病毒分离株（牛病毒性腹泻病毒1型）。所有母羊在感染后约100小时进行了卵巢子宫切除术。对生殖道和孕体的样本进行了组织学检查，并通过巢式逆转录-聚合酶链反应（RT-PCR）和免疫组织化学检测牛瘟病毒，通过非巢式RT-PCR检测干扰素-tau mRNA表达。尽管在母体或胎儿组织中未观察到组织病理学变化，但在所有9只母羊的生殖道和所有检测的孕体中均检测到了病毒。在手术时，9只母羊中只有2只表现出病毒血症。这项研究表明，在缺乏母体免疫力且尽管生殖道中有干扰素表达的情况下，牛瘟病毒可在4天内从自然感染部位传播至绵羊胎儿。
